1. Field of the Invention
The invention relates generally to systems and methods for cleaning the interior of tubular members. In particular aspects, the invention relates to methods and devices for scraping wellbore casing.
2. Description of the Related Art
Wellbore cleaning devices include casing scrapers and brushing devices. These mechanisms are used to remove mud, cement sheath, perforation burrs, rust, scale, paraffin, and other debris from the internal surface of wellbore casing. The casing scraper or brush is typically attached to a drill string for operation. The drill string and cleaning device are then disposed within the casing members to be scraped, and rotated.
Typical casing scrapers include a central scraping body and one or more scraping blades that extend radially outwardly therefrom. Conventional casing scrapers generally fall into one of two categories: rotating and non-rotating. With a rotating scraper, the scraping body and the scraping blades are securely affixed to each other so that both rotate with the drill string. In applications where the drill string is rotated for long periods of time, rotating scrapers can cause serious wear and damage to the interior surface of casing. With a non-rotating scraper, only the scraping body rotates with the drill string. The scraper blades are not affixed to the central scraping body, but are urged radially outwardly from it by compression springs in order to provide a force for removal of debris. An example of this type of arrangement is found in U.S. Pat. No. 7,311,141 issued to Tulloch et al.